Patents by Inventor Yasuyuki Oishi
Yasuyuki Oishi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 9143091Abstract: An amplifier module is expressed by a model having a first filter that is a linear time-invariant filter for limiting the bandwidth of an input signal, an amplifier unit that amplifies a signal output from the first filter, and a second filter that is a linear time-invariant filter for limiting the bandwidth of a signal output from the amplifier unit. A memoryless amplifier unit calculates an output from the amplifier module when being memoryless, using AM-to-AM distortion and AM-to-PM distortion of the amplifier unit. A cross-correlation calculating unit calculates a correlation between the signal output from the amplifier module and the output calculated by the memoryless amplifier unit and calculates an estimate of a transfer function of the first filter and the second filter. A distortion compensating unit compensates the input signal based on the estimate of the transfer function and outputs the signal to the amplifier module.Type: GrantFiled: October 23, 2013Date of Patent: September 22, 2015Assignee: FUJITSU LIMITEDInventors: Yasuyuki Oishi, Eisuke Fukuda, Yoshimasa Daido
-
Publication number: 20140292405Abstract: An amplification device includes: an amplitude adjustment circuit configured to adjust an amplitude level of an input signal so as to keep the amplitude level within a given range; an amplifier configured to amplify the adjusted signal; and a circuitry configured to change an amplitude level of the amplified signal, based on the amplitude level of the input signal and a first distortion compensation corresponding to the amplitude level of the input signal.Type: ApplicationFiled: March 25, 2014Publication date: October 2, 2014Applicant: FUJITSU LIMITEDInventors: Takeshi TAKANO, Shigekazu KIMURA, Ken TAMANOI, Masakazu KOJIMA, Toru MANIWA, Yasuyuki OISHI, Michiharu NAKAMURA, Kazuo NAGATANI
-
Publication number: 20140139287Abstract: An amplifier module is expressed by a model having a first filter that is a linear time-invariant filter for limiting the bandwidth of an input signal, an amplifier unit that amplifies a signal output from the first filter, and a second filter that is a linear time-invariant filter for limiting the bandwidth of a signal output from the amplifier unit. A memoryless amplifier unit calculates an output from the amplifier module when being memoryless, using AM-to-AM distortion and AM-to-PM distortion of the amplifier unit. A cross-correlation calculating unit calculates a correlation between the signal output from the amplifier module and the output calculated by the memoryless amplifier unit and calculates an estimate of a transfer function of the first filter and the second filter. A distortion compensating unit compensates the input signal based on the estimate of the transfer function and outputs the signal to the amplifier module.Type: ApplicationFiled: October 23, 2013Publication date: May 22, 2014Applicant: FUJITSU LIMITEDInventors: Yasuyuki OISHI, Eisuke FUKUDA, Yoshimasa DAIDO
-
Patent number: 8588711Abstract: A transmission apparatus includes an analog digital converter that performs sampling on a demodulated signal obtained by demodulating a part of an output signal, which is produced by amplifying a modulated signal of a baseband signal including a plurality of signals having frequencies separated from each other, at a sampling frequency lower than a frequency of a given intermodulation distortion component and converting the demodulated signal into a digital signal, a detection section that detects an aliasing component of the given intermodulation distortion component produced by the conversion of the analog digital converter, and a distortion compensation section that compensates an input signal to be modulated for the given intermodulation distortion component in accordance with the detected aliasing component.Type: GrantFiled: September 16, 2011Date of Patent: November 19, 2013Assignee: Fujitsu LimitedInventors: Hiroyoshi Ishikawa, Nobukazu Fudaba, Kazuo Nagatani, Yasuyuki Oishi
-
Patent number: 8508426Abstract: A variable directional antenna by means of a microstrip antenna and reactance change. The variable directional antenna has a structure to reduce sidelobes occurring when an element interval is reduced, and is structured in a three-element plane, having a feeding element and non-feeding elements provided at both sides of the feeding element. Each of the non-feeding elements provided at both sides of the feeding element has two split non-feeding elements two-divided into sizes of 1:2 in the lateral direction. The split non-feeding element divided into the size 1 is provided closer to the feeding element, and a reactance variable part is connected with the split non-feeding element divided into the size of 2. Alternatively, each of the non-feeding elements provided at both sides of the feeding element has two split non-feeding elements two-divided into sizes of 2:1 in the lateral direction.Type: GrantFiled: February 2, 2010Date of Patent: August 13, 2013Assignee: Fujitsu LimitedInventors: Atsushi Honda, Ichirou Ida, Yasuyuki Oishi
-
Patent number: 8493144Abstract: A distortion compensation device includes a distortion compensation unit which compensates for a distortion generated in a power amplifier by using a polynomial in which a signal to be input into a power amplifier is raised to a power of a degree N (N is an integer larger than 0) and the raised signal is delayed by a delay number K (K is an integer larger than 0), and a polynomial adjusting unit which adjusts the degree N or the delay number K of the polynomial based on a comparison between a prescribed value, which indicates a degree of variation of the distortion generated in the power amplifier and a threshold value.Type: GrantFiled: April 18, 2011Date of Patent: July 23, 2013Assignee: Fujitsu LimitedInventors: Hiroyoshi Ishikawa, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Kazuo Nagatani, Yasuyuki Oishi
-
Patent number: 8462052Abstract: An RFID tag having a tag antenna and an LSI chip, comprising: a power-supply pattern on which the LSI chip is mounted; a patch antenna that functions as the tag antenna; and a high-frequency connection section that makes a high-frequency connection between the power-supply pattern and the patch antenna. The high-frequency connection section is formed, for example, by forming a slot in the patch antenna, layering one end of a small dipole antenna that functions as the power-supply pattern over the slot so that it crosses over the slot, and supplying power from the small dipole antenna to the patch antenna.Type: GrantFiled: August 10, 2011Date of Patent: June 11, 2013Assignee: Fujitsu LimitedInventors: Takashi Yamagajo, Toru Maniwa, Manabu Kai, Yasuyuki Oishi, Yoshiyasu Sugimura, Shunji Baba
-
Publication number: 20120068768Abstract: A transmission apparatus includes an analog digital converter that performs sampling on a demodulated signal obtained by demodulating a part of an output signal, which is produced by amplifying a modulated signal of a baseband signal including a plurality of signals having frequencies separated from each other, at a sampling frequency lower than a frequency of a given intermodulation distortion component and converting the demodulated signal into a digital signal, a detection section that detects an aliasing component of the given intermodulation distortion component produced by the conversion of the analog digital converter, and a distortion compensation section that compensates an input signal to be modulated for the given intermodulation distortion component in accordance with the detected aliasing component.Type: ApplicationFiled: September 16, 2011Publication date: March 22, 2012Applicant: FUJITSU LIMITEDInventors: Hiroyoshi Ishikawa, Nobukazu Fudaba, Kazuo Nagatani, Yasuyuki Oishi
-
Publication number: 20110284643Abstract: An RFID tag having a tag antenna and an LSI chip, comprising: a power-supply pattern on which the LSI chip is mounted; a patch antenna that functions as the tag antenna; and a high-frequency connection section that makes a high-frequency connection between the power-supply pattern and the patch antenna. The high-frequency connection section is formed, for example, by forming a slot in the patch antenna, layering one end of a small dipole antenna that functions as the power-supply pattern over the slot so that it crosses over the slot, and supplying power from the smalI dipole antenna to the patch antenna.Type: ApplicationFiled: August 10, 2011Publication date: November 24, 2011Applicants: FUJITSU FRONTECH LIMITED, FUJITSU LIMITEDInventors: Takashi YAMAGAJO, Toru MANIWA, Manabu KAI, Yasuyuki OISHI, Yoshiyasu SUGIMURA, Shunji BABA
-
Patent number: 8064844Abstract: In a wireless communication apparatus in a time division duplex system, a transmission signal generation unit generates a transmission signal. A power amplifying device amplifies the generated transmission signal. A control signal generation device generates a drain voltage control signal for control of the drain voltage of the power amplifying device, and a gate voltage control signal for control of the gate voltage of the power amplifying device. The switch unit switches off the drain power supply of the power amplifying device during reception in the time division duplex system according to the drain voltage control signal. In addition, the power amplifying device sets a higher gate voltage during reception in the time division duplex system higher than during transmission according to the gate voltage control signal.Type: GrantFiled: November 28, 2008Date of Patent: November 22, 2011Assignee: Fujitsu LimitedInventors: Atsushi Honda, Kaoru Yokoo, Yasuyuki Oishi, Yoji Ohashi
-
Publication number: 20110260792Abstract: A distortion compensation device includes a distortion compensation unit which compensates for a distortion generated in a power amplifier by using a polynomial in which a signal to be input into a power amplifier is raised to a power of a degree N (N is an integer larger than 0) and the raised signal is delayed by a delay number K (K is an integer larger than 0), and a polynomial adjusting unit which adjusts the degree N or the delay number K of the polynomial based on a comparison between a prescribed value, which indicates a degree of variation of the distortion generated in the power amplifier and a threshold value.Type: ApplicationFiled: April 18, 2011Publication date: October 27, 2011Applicant: FUJITSU LIMITEDInventors: Hiroyoshi ISHIKAWA, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Kazuo Nagatani, Yasuyuki Oishi
-
Patent number: 8022878Abstract: An RFID tag having a tag antenna and an LSI chip, comprising: a power-supply pattern on which the LSI chip is mounted; a patch antenna that functions as the tag antenna; and a high-frequency connection section that makes a high-frequency connection between the power-supply pattern and the patch antenna. The high-frequency connection section is formed, for example, by forming a slot in the patch antenna, layering one end of a small dipole antenna that functions as the power-supply pattern over the slot so that it crosses over the slot, and supplying power from the small dipole antenna to the patch antenna.Type: GrantFiled: July 31, 2007Date of Patent: September 20, 2011Assignees: Fujitsu Limited, Fujitsu Frontech LimitedInventors: Takashi Yamagajo, Toru Maniwa, Manabu Kai, Yasuyuki Oishi, Yoshiyasu Sugimura, Shunji Baba
-
Patent number: 7973522Abstract: A DC/DC converter capable of controlling an output signal using a broadband signal input is provided. By employing the above DC/DC converter as a power supply, a highly efficient power amplifier can be configured. The above DC/DC converter includes two class-C amplifiers, a rectifier circuit connected between each output of the two class-C amplifiers, and an oscillator of a predetermined frequency signal. The predetermined frequency signal output from the oscillator is input to each of the two class-C amplifiers, and by controlling the phase difference of the predetermined frequency signal input to the two class-C amplifiers, the magnitude of a direct current voltage output from the rectifier circuit is made variable.Type: GrantFiled: December 27, 2007Date of Patent: July 5, 2011Assignee: Fujitsu LimitedInventors: Takeshi Takano, Yasuyuki Oishi, Tokuro Kubo, Toru Maniwa
-
Patent number: 7881404Abstract: A distortion correction control apparatus is for compensating for a burst distortion of a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes a generation unit that generates a distortion correction coefficient having reverse characteristics to the foregoing burst distortion; a unit that multiplies the distortion correction coefficient output from the generation unit by the input signal or adds the distortion correction coefficient output from the generation unit to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and an update unit that updates, based on the input signal and a branch signal fed back as an output signal of the transmission amplifier, parameters of functions used for adaptively generating the distortion correction coefficient, and that inputs the updated parameters to the generation unit.Type: GrantFiled: September 25, 2009Date of Patent: February 1, 2011Assignee: Fujitsu LimitedInventors: Hiroyoshi Ishikawa, Kazuo Nagatani, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Yasuyuki Oishi
-
Publication number: 20100188169Abstract: A reactance varying device comprises a voltage-controlled variable-capacitance circuit, a biasing circuit and an impedance transformer. The biasing circuit has a virtual AC ground node, which acts as a gateway to supply a bias voltage to the variable-capacitance circuit. The impedance transformer separates the variable-capacitance circuit from the AC ground node, as well as provides an inductive element to form a reactance varying LC tank.Type: ApplicationFiled: August 7, 2007Publication date: July 29, 2010Applicant: FUJITSU LIMITEDInventors: Sorwar Hossain, Yasuyuki Oishi
-
Publication number: 20100182214Abstract: A variable directional antenna by means of a microstrip antenna and reactance change. The variable directional antenna has a structure to reduce sidelobes occurring when an element interval is reduced, and is structured in a three-element plane, having a feeding element and non-feeding elements provided at both sides of the feeding element. Each of the non-feeding elements provided at both sides of the feeding element has two split non-feeding elements two-divided into sizes of 1:2 in the lateral direction. The split non-feeding element divided into the size 1 is provided closer to the feeding element, and a reactance variable part is connected with the split non-feeding element divided into the size of 2. Alternatively, each of the non-feeding elements provided at both sides of the feeding element has two split non-feeding elements two-divided into sizes of 2:1 in the lateral direction.Type: ApplicationFiled: February 2, 2010Publication date: July 22, 2010Applicant: FUJITSU LIMITEDInventors: Atsushi HONDA, Ichirou IDA, Yasuyuki OISHI
-
Patent number: 7746957Abstract: A distortion correction control apparatus is for compensating for a burst distortion in a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes a holding unit that stores a distortion correction coefficient having reverse characteristics to the burst distortion; a unit that multiplies the distortion correction coefficient read out from the holding unit by the input signal or adds the distortion correction coefficient read out from the holding unit to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and an update unit that updates, based on the input signal, the distortion correction coefficient of the last time, and a signal fed back as an output signal of the transmission amplifier, the distortion correction coefficient by an adaptive algorithm, and that inputs the updated distortion correction coefficient to the holding unit.Type: GrantFiled: September 25, 2009Date of Patent: June 29, 2010Assignee: Fujitsu LimitedInventors: Hiroyoshi Ishikawa, Kazuo Nagatani, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Yasuyuki Oishi
-
Publication number: 20100062733Abstract: A distortion correction control apparatus is for compensating for a burst distortion of a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes a generation unit that generates a distortion correction coefficient having reverse characteristics to the foregoing burst distortion; a unit that multiplies the distortion correction coefficient output from the generation unit by the input signal or adds the distortion correction coefficient output from the generation unit to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and an update unit that updates, based on the input signal and a branch signal fed back as an output signal of the transmission amplifier, parameters of functions used for adaptively generating the distortion correction coefficient, and that inputs the updated parameters to the generation unit.Type: ApplicationFiled: September 25, 2009Publication date: March 11, 2010Applicant: FUJITSU LIMITEDInventors: Hiroyoshi Ishikawa, Kazuo Nagatani, Hajime Hamada, Nobukazu Fudaba, Yuichi Utsunomiya, Yasuyuki Oishi
-
Patent number: 7663436Abstract: A power amplifier negates a memory effect and is applied a linearizer using a digital predistortion system even in an inexpensive device. The power amplifier compares an input signal power against a sampled component of an output power, and provides predistortion to the input signal power so as to minimize a difference as a result of the comparison. The power amplifier comprises a gain lookup table storing a gain coefficient value corresponding to a temperature address determined for an input power; a phase lookup table storing a phase coefficient value corresponding to the temperature address determined for the input power; a transversal filter, which is input with the input power, and which outputs the temperature address; and a coefficient multiplier modulating the input signal using a gain coefficient value and a phase coefficient value, which correspond to the temperature address and which are read out from the gain coefficient lookup table and the phase lookup table.Type: GrantFiled: December 14, 2007Date of Patent: February 16, 2010Assignee: Fujitsu LimitedInventors: Takeshi Takano, Yasuyuki Oishi, Toru Maniwa
-
Publication number: 20100014609Abstract: A distortion correction control apparatus is for compensating for a burst distortion in a transmission amplifier caused by a burst of an input signal of a transmission target. The apparatus includes a holding unit that stores a distortion correction coefficient having reverse characteristics to the burst distortion; a unit that multiplies the distortion correction coefficient read out from the holding unit by the input signal or adds the distortion correction coefficient read out from the holding unit to the input signal, upon reception of burst information notifying of switching between presence and absence of the input signal; and an update unit that updates, based on the input signal, the distortion correction coefficient of the last time, and a signal fed back as an output signal of the transmission amplifier, the distortion correction coefficient by an adaptive algorithm, and that inputs the updated distortion correction coefficient to the holding unit.Type: ApplicationFiled: September 25, 2009Publication date: January 21, 2010Applicant: FUJITSU LIMITEDInventors: Hiroyoshi Ishikawa, Kazuo Nagatani, Hajime HAMADA, Nobukazu Fudaba, Yuichi Utsunomiya, Yasuyuki Oishi